initialize float4 (core.simd)

[Bogdan]

Here's a cleaned up version:

```
import std.stdio;
import core.simd;

void main()
{
   float[4] values = [1.0f, 2.0f, 3.0f, 4.0f];
   float delta = 15.0f;

   writeln(doSimd(values, delta));

}

float[4] doSimd(float[4] values, float delta)
{
   float4 v_delta = delta;
   float4 v_values = values;

   v_values = __simd(XMM.ADDPS, v_values, v_delta);

   return [v_values[0], v_values[1],v_values[2],v_values[3]];
}
```

The problem is with initializing v_values.